The present invention, in some embodiments thereof, relates to a modulator constructed from optical closed-loop resonators, such as ring, disk, and elongated ring, or race-track, resonators and, more particularly, but not exclusively, to a modulator constructed from a micro-ring resonator having multiple electrodes.
Attempts to apply photonic technologies to data processing have been tried for several decades. Yet, their implementation in practical systems remains limited and fails to penetrate practical processors. Many demonstrated optical devices remain oversized, are based on exotic materials and need complicated interfacing with other electronic components. Recent developments in micro-photonics and novel interfacing schemes may realize photonic components for fast communication and signal processing that overcome the above-mentioned shortcomings but only if basic physical and mathematical challenges can be solved.
A modulator based on an optical ring resonator is a set of waveguides in which at least one is a closed loop resonator coupled to some sort of light input and output. (These can be, but are not limited to being, waveguides.) When light of the resonant wavelength is passed through the loop from the input waveguide, it builds up in intensity over multiple round-trips due to constructive interference and is output to the output bus waveguide. The light may couple to the loop at the input and output. The output bus is the same as the input bus: input port, through/output port and in add-drop configuration, and there is an additional output port which is the drop port. Because discrete wavelengths are at resonance within the loop, the optical ring resonator functions as a filter.
To date the micro-ring resonator is a resonant light-confining structure with enhanced sensitivity to small changes in refractive index of the silicon.